Is a mandatory intensive care unit stay needed after liver transplantation? Feasibility of fast-tracking to the surgical ward after liver transplantation

Authors


Abstract

The continuation of hemodynamic, respiratory, and metabolic support for a variable period after liver transplantation (LT) in the intensive care unit (ICU) is considered routine by many transplant programs. However, some LT recipients may be liberated from mechanical ventilation shortly after the discontinuation of anesthesia. These patients might be appropriately discharged from the postanesthesia care unit (PACU) to the surgical ward and bypass the ICU entirely. In 2002, our program started a fast-tracking program: select LT recipients are transferred from the operating room to the PACU for recovery and tracheal extubation with a subsequent transfer to the ward, and the ICU stay is completely eliminated. Between January 1, 2003 and December 31, 2007, 1045 patients underwent LT at our transplant program; 175 patients were excluded from the study. Five hundred twenty-three of the remaining 870 patients (60.10%) were fast-tracked to the surgical ward, and 347 (39.90%) were admitted to the ICU after LT. The failure rate after fast-tracking to the surgical ward was 1.90%. The groups were significantly different with respect to the recipient age, the raw Model for End-Stage Liver Disease (MELD) score at the time of LT, the recipient body mass index (BMI), the retransplantation status, the operative time, the warm ischemia time, and the intraoperative transfusion requirements. A multivariate logistic regression analysis revealed that the raw MELD score at the time of LT, the operative time, the intraoperative transfusion requirements, the recipient age, the recipient BMI, and the absence of hepatocellular cancer/cholangiocarcinoma were significant predictors of ICU admission. In conclusion, we are reporting the largest single-center experience demonstrating the feasibility of bypassing an ICU stay after LT. Liver Transpl 18:361–369, 2012. © 2012 AASLD.

Liver transplantation (LT) is a lifesaving operation for patients with end-stage liver disease (ESLD). Patients with ESLD are ill and often require intensive medical and surgical care before and after LT. The continuation of hemodynamic, respiratory, and metabolic monitoring and support for a variable period after the operation in the intensive care unit (ICU) is considered routine by many LT programs.1, 2 Improvements in the preoperative workup, surgical techniques, and intraoperative anesthesia care of LT recipients in the last decade have resulted in shorter hospital stays, fewer perioperative complications, and increased patient survival. In particular, a balanced anesthetic technique that uses inhaled anesthetics judiciously supplemented with small doses of narcotics and benzodiazepines facilitates rapid arousal from general anesthesia. This approach enables early extubation and liberation from mechanical ventilation.3, 4 To varying degrees, some LT programs have adapted this practice to facilitate early tracheal extubation, but few have tried to fast-track LT recipients to the surgical ward and bypass the ICU altogether.5-10 Bypassing the ICU has been previously reported only in a small case series.5 The term fast-tracking has been used for this approach. Unfortunately, the same term has also been used to describe early extubation with a variable ICU stay. In this article, the term fast-tracking is used for the early extubation of LT recipients, their recovery from anesthesia in the postanesthesia care unit (PACU), and their subsequent transfer to the surgical ward with the complete elimination of an ICU stay. This practice has been consistently used since 2002. Rather than establishing criteria at the beginning, the decision to transfer a patient to the ICU versus fast-tracking to the surgical ward was left to the attending surgeon and the anesthesiologist of each case. The clinical judgments of both physicians are determinant in each case. In this retrospective analysis, we have sought to identify the recipient, donor, and operative elements that correlate with successful fast-tracking after LT.

Abbreviations:

ABG, arterial blood gas; BMI, body mass index; CCA, cholangiocarcinoma; CIT, cold ischemia time; CRRT, continuous renal replacement therapy; CVVHD, continuous venovenous hemodialysis; DRI, donor risk index; ESLD, end-stage liver disease; HCC, hepatocellular cancer; HCV, hepatitis C virus; ICU, intensive care unit; LT, liver transplantation; MELD, Model for End-Stage Liver Disease; OR, operating room; PACU, postanesthesia care unit; POD, postoperative day; PRBC, packed red blood cell; WIT, warm ischemia time.

PATIENTS AND METHODS

We retrospectively identified all adult LT recipients who underwent transplantation between January 2003 and December 2007 at Mayo Clinic Florida. This convenience sample was selected because it reflected stability in medical and surgical practice and personnel. Approval for the chart review and the analysis was obtained from the Mayo Clinic institutional review board. Fast-tracking was defined as recovery from anesthesia [including extubation of the airway in the operating room (OR) or PACU] and a subsequent transfer to the surgical ward without the need for admission to the ICU. The recipient data included the following: age, sex, liver disease etiology, hepatocellular carcinoma (HCC) or cholangiocarcinoma (CCA) as a pretransplant secondary diagnosis, body mass index (BMI), raw Model for End-Stage Liver Disease (MELD) score at the time of transplantation, and follow-up time. The perioperative information included the following: operative time, intraoperative transfusion volume, length of hospital stay, and length of ICU stay.

Detailed information about the liver donors was obtained from the Mayo Clinic Florida procurement database. The donor information included the following: age, sex, cold ischemia time (CIT), warm ischemia time (WIT), donor risk index (DRI) and individual components of the DRI, and donation after cardiac death/donation after brain death status. CIT was defined as the time from the infusion of the cold preservation solution to the portal reperfusion of the liver graft in the recipient. Patient and graft survival at 1, 3, and 5 years were recorded. To determine whether hospital logistics (instead of medical/surgical factors) played any role in the transfer to the ICU, LT recipients who stayed in the ICU for 1 day or less were retrospectively identified, and their characteristics were compared to those of the fast-tracked LT recipients. For all fast-tracked patients, the length of the PACU stay was retrospectively recorded.

Resource utilization was evaluated in a subset of patients because of the large sample size. For patients who underwent LT in 2007, we collected the number of arterial blood gas (ABG) examinations, the number of chest X-rays, and the overall room charges within the first 7 days after LT. Comparisons of fast-tracked patients and ICU-bound patients (2007) as well as fast-tracked patients (2007) and all patients who stayed for 1 day or less in the ICU (2003-2007) were performed.

We excluded from the analysis patients who died during surgery, patients who received partial liver grafts, patients who were in the ICU immediately before LT, patients who required intraoperative renal replacement therapy, and patients who underwent multiorgan transplantation or underwent cardiac surgery and LT in combination.

Surgical and Anesthetic Techniques

All transplants were performed with the inferior vena cava preservation technique (piggyback) without a portocaval shunt or caval clamping. All were deceased donor whole organ transplants. For anesthesia, propofol (1-2 mg/kg), fentanyl (150-250 μg), and succinylcholine (1-1.5 mg/kg) were used to facilitate the rapid sequential induction of anesthesia and intubation. Anesthesia was maintained with isoflurane titrated to a minimum alveolar concentration of 0.5 to 1.25. The muscle relaxant cisatracurium was initially given at a dose of 0.1 to 0.25 mg/kg, and then it was dosed to maintain 1 twitch with train of 4 ulnar nerve stimulation. Fentanyl boluses were administered judiciously so that the total fentanyl dose did not exceed 10 μg/kg. Most fentanyl was given during the dissection phase of the operation; small amounts (50-100 μg) were titrated after reperfusion if the hemodynamics demanded it. At the end of the procedure, the administration of isoflurane was reduced and stopped. During skin closure, the muscle relaxant was reversed with neostigmine and glycopyrrolate. The end tidal carbon dioxide levels were allowed to rise higher than 40 mm Hg to facilitate spontaneous breathing.

The decision to fast-track a patient instead of transferring him or her to the ICU was made by the transplant surgeon and the anesthesiologist according to their clinical judgment rather than a defined clinical protocol at the time of LT; a critical care specialist was involved in select cases. Fast-tracked patients were initially transferred to the PACU immediately after LT. These patients were extubated in the OR or the PACU when the standard extubation criteria were met (spontaneous respiration, an adequate tidal volume, and the ability to perform a 5-second head lift). The PACU was in operation 24 hours a day, 7 days a week, and it was staffed with appropriately trained registered nurses supervised by anesthesiologists. The anesthesiologist in each case was immediately available to the LT patient until the patient was transferred to the surgical ward. Logistics, including the availability of 1:1 nursing in the surgical ward, and clinical characteristics, including the full recovery of spontaneous respiration and the absence of hemodynamic instability, were ensured before the ward transfer. Before the transfer to the transplant surgical ward, invasive monitoring devices such as arterial lines and pulmonary artery catheters were removed. The surgical ward was a 28-bed nursing unit dedicated to patients before and after solid organ transplantation, and it was not staffed by the critical care team. In the surgical ward, a 1:1 nurse-to-patient ratio was maintained for the first 12 to 24 hours after LT. The patients were monitored by continuous pulse oximetry, continuous electrocardiography, central venous pressure measurements, and noninvasive blood pressure measurements. The hemoglobin concentration was measured every 6 hours in the first 24 hours after LT or when this was clinically indicated. Fast-track failure was defined as initial fast-tracking to the surgical ward followed by a transfer to the ICU within 72 hours after the completion of LT. The reasons for fast-track failure and the need for subsequent intubation and mechanical ventilation were determined retrospectively.

Statistical Analysis

Comparisons of continuous and categorical variables between groups were performed with t tests and χ2 tests, respectively. Patient and surgery-associated variables with P values of 0.10 or less on a t test or a χ2 test and variables of clinical interest were explored as possible predictors of ICU admission after LT with logistic regression. Variables that were associated with ICU admission with a P value of 0.10 or less in a single-variable analysis were included in a multivariate model. A P value of 0.05 or less was considered statistically significant. Statistical analyses were performed with SPSS 17.0 (SPSS, Chicago, IL).

RESULTS

Between January 1, 2003 and December 31, 2007, 1045 patients underwent LT through the transplant program of Mayo Clinic Florida (Fig. 1). One hundred seventy-five patients were excluded from the study for the following reasons (there was more than 1 reason for some patients): intraoperative death (n = 8), split graft transplantation (n = 1), admission to the ICU immediately before LT (n = 71), intraoperative renal replacement therapy (n = 109), multiorgan transplantation [n = 42: liver-kidney transplantation (38), liver-lung transplantation (1), liver-kidney-pancreas transplantation (1), and liver-pancreas transplantation (2)], and a major heart procedure at the time of orthotopic LT [n = 7: an aortic valve replacement (1), a coronary artery bypass graft (5), and an aortic valve replacement in combination with a coronary artery bypass graft (1)].

Figure 1.

Distribution of 1045 LT recipients between 2003 and 2007.

Five hundred twenty-three of the remaining 870 patients (60.10%) were fast-tracked to the surgical ward, and 347 (39.90%) were admitted to the ICU after LT. The annual distributions of fast-tracked patients and ICU-admitted patients are illustrated in Table 1. During this period, the percentage of fast-tracked patients ranged from 52.30% to 64.40%. The mean length of stay in the PACU for fast-tracked patients was 162 ± 49 minutes (range = 67-340 minutes, median = 172 minutes).

Table 1. Annual Distributions of LT Recipients Who Were Fast-Tracked and LT Recipients Who Were Admitted to the ICU
Transplant YearFast-Tracked Patients (n = 523)ICU Patients (n = 347)
  1. NOTE: The data are presented as numbers and percentages. P = 0.018.

200385 (56.7)65 (43.3)
2004132 (64.4)73 (35.6)
2005125 (60.7)81 (39.3)
2006114 (63.0)67 (37.0)
200767 (52.3)61 (47.7)

Ten patients (1.90%) who were initially fast-tracked to the surgical ward had to be transferred to the ICU within 72 hours after the completion of LT: 4 patients required exploratory laparotomy [3 for intra-abdominal bleeding on postoperative day (POD) 1 and 1 for an enteric leak on POD 3], 3 patients had cardiac complications [atrial fibrillation on POD 2 (2) and myocardial infarction on POD 2 (1)], 1 patient experienced fluid overload on POD 3, 1 patient had respiratory distress due to aspiration on POD 2, and 1 patient suffered acute renal failure on POD 3.

The recipient, donor, and perioperative characteristics are summarized in Table 2. The groups were significantly different with respect to the recipient age, the raw MELD score at the time of LT, the recipient BMI, and the retransplantation status. Patients in the fast-tracked group were more likely to have had hepatitis C virus (HCV) as their liver disease etiology and HCC or CCA as a secondary diagnosis. The donor characteristics (including the DRI) were similar for the groups. Among the surgery-associated factors, there were significant differences in the operative times, WITs, and intraoperative transfusion requirements: the fast-tracked patients had shorter operative times and shorter WITs and required fewer blood/blood product transfusions. The overall hospital stays and the pretransplant hospital stays were also different: the fast-tracked patients had significantly shorter hospital stays.

Table 2. Donor, Recipient, and Perioperative Characteristics of LT Recipients Who Were Successfully Fast-Tracked and LT Recipients Who Were Admitted to the ICU
 Fast-Tracked Patients (n = 513)*ICU Patients (n = 357)P Value
  • NOTE: Continuous variables are presented as means and standard deviations; the 25th, 50th, and 75th percentiles are shown in parentheses.

  • *

    Ten of the original 523 fast-tracked patients were moved from the surgical ward to the ICU.

  • Caucasian patients versus non-Caucasian patients.

Recipient variables   
 Age (years)53.92 ± 10.93 (49, 54, 61)57.09 ± 9.36 (51, 57, 64)<0.001
 Sex: male [n (%)]357 (69.6)237 (66.4)0.32
 Raw MELD score15.50 ± 5.52 (12, 15, 19)18.19 ± 6.86 (13, 17, 22)<0.001
 BMI (kg/m2)28.39 ± 5.94 (24.2, 27.4, 31.55)29.04 ± 6.27 (24.4, 28.1, 38.6)0.12
 Race [n (%)]  0.33
  Caucasian468 (91.2)333 (93.3) 
  African American24 (4.7)13 (3.6) 
  Asian Pacific15 (2.9)3 (0.8) 
  Asian Indian1 (0.2)2 (0.6) 
  Mideastern Arabic4 (0.8)4 (1.1) 
  Native American1 (0.2)1 (0.3) 
  Pacific Islander0 (0.0)1 (0.3) 
 Previous LT [n (%)]26 (5.1)41 (11.5)<0.001
 HCV [n (%)]210 (40.9)118 (33.1)0.02
 HCC/CCA [n (%)]159 (31.0)64 (17.9)<0.001
  CCA21 (4.1)6 (1.7)0.04
  HCC138 (26.9)58 (16.2)<0.001
Donor/graft variables   
 Age (years)48.20 ± 19.15 (34.5, 49.0, 62.0)46.22 ± 18.25 (30.5, 48.0, 59.0)0.10
 Sex: male [n (%)]268 (52.2)203 (56.9)0.25
 DRI1.74 ± 0.48 (1.36, 1.69, 2.08)1.72 ± 0.47 (1.39, 1.66, 2.03)0.43
 Donation after cardiac death [n (%)]60 (11.7)42 (11.8)0.98
Surgery-associated variables   
 Surgery time (hours)4.14 ± 1.50 (3.0, 3.7, 5.07)4.98 ± 1.79 (3.51, 4.78, 6.11)<0.001
 PACU stay (minutes)161.64 ± 49.0 (124, 172, 225) 
 WIT (minutes)31.82 ± 8.67 (25, 30, 38)36.27 ± 13.69 (27, 35, 41)<0.001
 CIT (hours)6.73 ± 1.98 (5.23, 6.32, 7.85)6.85 ± 1.80 (5.6, 6.6, 7.94)0.92
 PRBC transfusion (U)7.27 ± 6.95 (4, 6, 9)13.15 ± 12.18 (6, 10, 16)<0.001
 Platelets (U)2.41 ± 1.79 (1, 2, 3)3.93 ± 3.15 (2, 3, 5)<0.001
 Fresh frozen plasma (U)7.60 ± 6.45 (4, 7, 10)12.87 ± 10.41 (7, 10, 15)<0.001
 Cryoprecipitate (U)6.30 ± 8.16 (0, 0, 10)12.76±13.48 (0, 10, 20)<0.001
Hospital stay   
 Length of stay (days)9.06 ± 6.62 (7, 8, 9)21.16 ± 28.34 (8, 11, 22)<0.001
 Pre-LT stay (days)0.5 ± 1.54 (0, 0, 1)2.48 ± 6.93 (0, 0, 1)<0.001
 Post-LT stay (days)8.62 ± 7.77 (6, 7, 9)18.76 ± 26.10 (8, 10, 19)<0.001

A logistic regression analysis was used to identify recipient, surgical, and donor organ characteristics predicting ICU admission after LT (Table 3). In a univariate analysis, the following were significant predictors of ICU admission: raw MELD score at the time of LT, operative time, WIT, intraoperative transfusion requirements, recipient age, recipient BMI, non-HCV etiology, and absence of HCC/CCA. In a multivariate analysis, all but non-HCV etiology and WIT remained significant predictors of ICU admission.

Table 3. Univariate and Multivariate Analyses of Factors Predicting Admission to the ICU After LT
 Univariate AnalysisMultivariate Analysis
Odds Ratio (95% Confidence Interval)P ValueOdds Ratio (95% Confidence Interval)P Value
HCC/CCA as secondary diagnosis0.502 (0.363-0.692)<0.0010.547 (0.369-0.809)0.003
HCV0.727 (0.551-0.961)0.030.908 (0.650-1.270)0.58
Operative time (15-minute increase)1.077 (1.054-1.101)<0.0011.082 (1.056-1.110)<0.001
PRBC transfusion (5-U increase)1.125 (1.095-1.155)<0.0011.123 (1.091-1.155)<0.001
Raw MELD score1.072 (1.049-1.096)<0.0011.069 (1.042-1.097)<0.001
Recipient age (years)1.028 (1.014-1.042)<0.0011.043 (1.026-1.060)<0.001
BMI (kg/m2)1.029 (1.007-1.052)0.011.032 (1.006-1.059)0.02
Previous LT2.717 (1.640-4.503)<0.0012.298 (1.241-4.255)0.008
Pre-LT hospital stay (1-day increase)1.263 (1.160-1.376)<0.0011.188 (1.090-1.295)<0.001
WIT (minutes)1.034 (1.020-1.048)<0.0011.002 (0.984-1.021)0.81
DRI (0.1-point increase)0.985 (0.957-1.013)0.98  

Forty recipients stayed in the ICU for 1 day or less after LT (Table 4). Two of the recipient, donor, and operative characteristics were significantly different for the ICU-admitted recipients and the fast-tracked recipients: the operative time (4.79 ±1.73 versus 4.13 ± 1.48 hours, P = 0.006) and the transfusion of intraoperative packed red blood cells (PRBCs; 15.05 ± 15.81 versus 7.27 ± 6.92 U, P = 0.004). To determine whether hospital logistics (rather than medical/surgical factors) played any role in the transfer of patients to the ICU in this subgroup, we compared 11 recipients who were admitted to the ICU between 6 AM and 6 PM and 29 recipients who were admitted to the ICU between 6 PM and 6 AM: the operative times (4.16 ± 1.73 versus 5.03 ± 1.70 hours, P = 0.012) and intraoperative PRBC transfusions (12.91 ± 11.66 versus 10.27 ± 8.46 U, P = 0.011) were similar for these 2 groups.

Table 4. Comparison of Recipient, Donor, and Intraoperative Characteristics of LT Recipients Who Were Successfully Fast-Tracked and LT Recipients Who Stayed in the ICU for 1 Day or Less
FactorFast-Tracked Patients (n = 513)*ICU Patients for 1 Day or Less (n = 40)P Value
  • NOTE: The data are presented as means and standard deviations; the 25th, 50th, and 75th percentiles are shown in parentheses.

  • *

    Ten of the original 523 fast-tracked patients were moved from the surgical ward to the ICU.

Recipient age (years)54.05 ± 10.91 (49, 54, 61.5)55.23 ± 9.27 (49, 56, 65)0.49
Raw MELD score15.55 ± 5.54 (12, 15, 19)16.59 ± 5.67 (13, 15, 21)0.21
BMI (kg/m2)28.36 ± 5.95 (24.2, 27.4, 31.5)28.77 ± 5.34 (24.7, 28.6, 32.5)0.66
Donor age (years)47.96 ± 19.18 (34, 49, 62)48.18 ± 14.26 (39, 48, 60)0.98
DRI1.74 ± 0.47 (1.37, 1.69, 2.07)1.66 ± 0.46 (1.26, 1.62, 2.06)0.24
PRBC transfusion (U)7.27 ± 6.92 (4, 6, 9)15.05 ± 15.81 (7, 9, 16)0.004
Surgery time (hours)4.13 ± 1.48 (3.0, 3.71. 5.03)4.79 ± 1.73 (3.15, 4.45, 5.93)0.006
CIT (hours)6.74 ± 1.98 (5.28, 6.37, 7.84)6.55 ± 1.78 (5.42, 6.70, 7.60)0.59
WIT (minutes)31.95 ± 8.72 (25.0, 30.0, 38.0)34.38 ± 9.01 (26.0, 35.0, 40.0)0.07
Hospital stay (days)9.33 ± 11.80 (7, 8, 9)8.05 ± 2.99 (7, 7, 8)0.33
Post-LT hospital stay (days)9.32 ± 11.80 (6, 7, 9)7.25 ± 1.17 (6, 7, 8)0.27

Resource utilization was evaluated for patients who underwent LT in 2007 (Table 5). Patients who were fast-tracked to the surgical ward had significantly fewer ABG measurements (1.35 ± 1.58 for fast-tracked patients versus 5.17 ± 3.83 for ICU patients, P < 0.001), significantly fewer chest X-rays (2.45 ± 1.33 versus 5.29 ± 2.75, P < 0.001), and significantly lower 7-day room charges (5279.46 ± 1411.79 versus 7829.81 ± 1661.36 USD, P < 0.001). When patients who were fast-tracked to the surgical ward (2007) were compared to 40 patients who stayed for 1 day or less in the ICU (2003-2007), there were significant differences in the number of ABG measurements (1.35 ± 1.58 versus 2.21 ± 1.40, P = 0.007), the number of chest X-rays (2.45 ± 1.33 versus 3.63 ± 2.04, P = 0.001), and the 3-day room charges (2598.38 ± 566.23 versus 3465.0 ± 1723.96 USD, P = 0.004); the 7-day room charges were similar for the 2 groups.

Table 5. Comparison of ABG, Chest X-Ray, and Room Charges Within the First 7 Days After LT for Patients Who Were Fast-Tracked, Patients Who Stayed in the ICU, and Patients Who Stayed in the ICU for 1 Day or Less
 Fast-Tracked Patients (n = 65)*ICU Patients (n = 63)*P ValueICU Patients for 1 Day or Less (n = 40)P Value§
  • NOTE: The data are presented as means and standard deviations; the 25th, 50th, and 75th percentiles are shown in parentheses.

  • *

    The patients underwent transplantation in 2007.

  • Fast-tracked patients versus ICU patients.

  • The patients underwent transplantation between 2003 and 2007. The charges are set at 2007 prices.

  • §

    Fast-tracked patients versus ICU patients for 1 day or less.

ABG examinations (n)1.35 ± 1.58 (1.0, 1.0, 1.0)5.17 ± 3.83 (3.0, 4.0, 6.0)<0.0012.21 ± 1.40 (1.0, 2.0, 3.0)0.007
7-day ABG charges (USD)139.17 ± 162.3 (103, 103, 103)532.32 ± 394.63 (309, 412, 618)<0.001227.45 ± 144.03 (103, 206, 309)0.007
Chest X-rays (n)2.45 ± 1.33 (2.0, 2.0, 3.0)5.29 ± 2.75 (3.0, 5.0, 7.0)<0.0013.63 ± 2.04 (2.75, 3.0, 4.0)0.001
7-day chest X-ray charges (USD)243.14 ± 137.13 (200, 200, 315)495.11 ± 266.93 (285, 455, 680)<0.001338.95 ± 186.94 (263.75, 285, 370)0.004
3-day room charges (USD)2598.38 ± 566.23 (1830, 2430, 3030)3712.08 ± 562.37 (3350, 4110, 4110)<0.0013465.0 ± 1723.96 (2590, 2975, 3642)0.004
7-day room charges (USD)5279.46 ± 1411.79 (4372.5, 5150, 6670)7829.81 ± 1661.36 (6420, 7790, 8510)<0.0015983.68 ± 2323.23 (4382.5, 5430, 7072.5)0.41

The graft and patient survival rates are summarized in Figs. 2 and 3, respectively. The 1-year graft survival rate was higher for the fast-tracked group versus the ICU group (89.70% versus 85.30%, P = 0.043), whereas the 3- and 5-year graft survival rates were similar for the 2 groups. The patient survival rates were statistically different for the fast-tracked patients and the ICU patients at 1 (94.50% versus 89.60%, P = 0.007), 3 (87.00% versus 82.40%, P = 0.005), and 5 years (81.30% versus 74.70%, P = 0.003). The 30-day mortality rates were not significantly different for the 2 groups: 4 patients (0.80%) in the fast-tracked group and 6 patients (1.70%) in the ICU group died within the first 30 days after LT (P = 0.022).

Figure 2.

Graft survival rates of patients who were fast-tracked and patients who were admitted to the ICU.

Figure 3.

Survival rates of patients who were fast-tracked and patients who were admitted to the ICU.

DISCUSSION

This retrospective study demonstrates that at a large-volume transplant center, fast-tracking (ie, the early extubation of LT recipients in the OR or PACU, their recovery from anesthesia in the PACU, and their transfer to the surgical ward without an ICU stay) is feasible and can be accomplished at a lower cost without patient safety being compromised. Sixty percent of the eligible LT recipients were successfully fast-tracked to the surgical ward. The failure rate after fast-tracking to the surgical ward was low. A detailed analysis of our data set has identified several recipient and surgery-related factors differentiating fast-tracking from direct ICU admission after LT. This analysis offers the potential for ongoing quality improvements in our program and by extension may benefit similar LT recipients in other programs.

After LT, patients are critically ill and have varying requirements for hemodynamic and ventilatory support.1 The continuation of mechanical ventilation for a variable period of time and admission to the ICU after LT are common practices in many LT programs.1, 2 However, improvements in surgical and anesthetic techniques in the last decade have reduced the acuity of these patients after transplant surgery. Increasingly, patients require less invasive monitoring and intensive care. In addition, the physiological advantages of immediate extubation have been demonstrated before: increased venous return to the heart, increased cardiac output, and increased hepatic blood flow, all of which contribute to improved early graft function.11, 12 Early extubation after transplant surgery for a subgroup of recipients has been proposed and tried by different LT programs.5-10 This trend has begged the question whether ICU care is needed by protocol for all LT recipients.3, 5-10

Building on previous reports in the LT literature, our program started early extubation and fast-tracking to the surgical ward in 2002. At the start of this program, we believed that a subset of relatively healthy patients with good physiological reserves could benefit from this approach. The decision to pursue early tracheal extubation and fast-tracking is jointly made by the attending anesthesiologist and the surgeon of the case and at times involves a critical care specialist. The decision to fast-track patients to the surgical ward is made during the second half of the LT operation, usually after reperfusion of the graft. The decision is not protocolized, although factors such as hemodynamic stability, the absence of ongoing hemorrhaging, the absence of evidence of early graft dysfunction or vascular problems, and the need for prolonged ventilatory support are considered. Patients who go to the OR from the ICU, require intraoperative dialysis, receive multiple organs, or undergo combined cardiac procedures (valve replacement and coronary revascularization) at the time of transplantation are admitted directly to the ICU for postoperative care and are not the subjects of this investigation. Our fast-tracking program has been successful over the years and continues to be a part of our practice. Several facets of care at the surgical ward of Mayo Clinic Florida ensure the success of this program. These include the 24-hour availability of the PACU, the 1:1 nurse-to-patient ratio for 12 to 24 hours after LT in the surgical ward, and the tight integration of the transplant critical care service with transplant surgery, anesthesiology, and hepatology (which allows evaluations in the OR, PACU, or surgical ward at any time).

Although we believe that there are patients who benefit from mechanical ventilation and a stay in the ICU, our experience has demonstrated that a subset of LT recipients can safely bypass the ICU after early extubation. A successful prediction depends on the recipient's pretransplant condition, intraoperative events, and the ability of the anesthesiologist and the surgeon to predict posttransplant problems. The fundamental precept behind early extubation and fast-tracking is that medical care can be tailored to the needs of the patient in an effort to address interpatient variability.1, 3 The practice of keeping all recipients on mechanical ventilation assumes that all recipients and all operations are the same. Although the practice of prolonged ventilation and a stay in the ICU provides more time for assessing patients for potential immediate complications after LT (eg, hemorrhaging), it may not prevent complications. The physiological advantages of the early termination of ventilation may actually improve early graft function.12 The assumption that mandatory ventilation and a mandatory ICU stay will be advantageous in terms of graft and patient survival may not be true. For LT recipients in the ICU, a possible way of shortening the ICU stay is to shorten the ventilation period. However, early extubation may not lead to a shorter stay in the ICU. Findlay et al.9 reported that immediate tracheal extubation did not translate into a decrease in the ICU stay. This finding was contradicted by another small study.10 In our study, the overall hospital stay and the posttransplant hospital stay were significantly shorter for the fast-tracked patients. Although this was partially related to the fact that the patients in the fast-tracked group were healthier, the avoidance of a mandatory ICU stay may have played a role. The retrospective nature of this analysis makes it impossible to delineate the risks and benefits of fast-tracking alone: a prospective study of similarly ill LT recipients randomized to the ICU or fast-tracking with other factors held constant would be required. Similarly to some previous studies, intraoperative red blood cell transfusions, the retransplantation status, and high MELD scores were significantly associated with late extubation and a prolonged ICU stay.8

The implementation of a sickest-first prioritization–based allocation system using the MELD score has ameliorated equity concerns. However, there is evidence that the MELD score correlates with posttransplant morbidity.13 In addition, there are significant regional differences in MELD scores; consequently, fast-tracking may not easily be performed in every institution in a widespread manner.14, 15 We agree with the authors of previous publications that transplant centers have different practices and philosophies not reflected by individual recipient and donor characteristics. The increasing severity of ESLD, as reflected by MELD scores, is associated with higher morbidity, which in turn increases the costs of care and reduces the profitability margin for transplant centers. In a previous publication,16 patients with MELD scores greater than 15 were found to have 49% higher costs; the major cost drivers were higher room, laboratory, radiology, and pharmacy costs. Despite significant increases in costs, revenues increased only 24%, and this resulted in a widening loss-income gap for transplant centers. Even though many cost-related factors are not within a transplant center's control, certain practices, such as the identification of recipients who could be extubated early and fast-tracked to the ward, could decrease overall costs.16-18 One previous study demonstrated that marginal liver grafts with high DRIs resulted in higher overall care costs.18 In contrast to United Network for Organ Sharing data,17, 18 the DRI was not found to be a significant factor in our analysis. This is at least partially related to the similar mean DRI scores of the 2 groups.

Despite regional differences in the acuity of patients undergoing LT, there are subsets of patients in each region who undergo LT with relatively low raw MELD scores (eg, patients with higher assigned MELD scores due to a diagnosis of HCC or CCA).13, 15, 18 These patients might be ideal candidates for fast-tracking. Direct comparisons of different programs are difficult because of different patient populations, practices, and perioperative protocols. Every program can determine if this is feasible according to its facilities and personnel. For similar results, the key elements identified from our practice at Mayo Clinic Florida would have to be secured at transplant programs considering a similar approach. These include the following: the availability of the PACU 24 hours a day, 7 days a week, 365 days a year; a 1:1 nurse-to-patient ratio in the surgical ward for 12 to 24 hours after LT; and the close integration of the critical care service so that input can be provided at any stage (including the OR, PACU, and surgical ward). The expenses associated with this approach are offset by the elimination of an ICU stay. Cost savings are a strong impetus for considering such a protocol. With constraints on health care resources, providers need to contain costs because the profitability of transplant programs depends on the difference between the reimbursements and the costs. Patients who bypass the ICU, as long as this is done safely, will use fewer resources; this includes but is not limited to ventilation, routine chest X-rays, ABG examinations, and nursing care. The preoperative identification of patients who are likely to be fast-tracked is important because it could allow economic savings through the optimization of hospital resources. Also, the determination of which patients will have a short stay in the ICU and which factors will be in play will help with hospital resource planning on a daily basis and in the long term.

Critics might argue that the decreased number of ICU admissions came at the expense of an increased PACU burden. However, the mean length of stay in the PACU for fast-tracked patients was 162 ± 49 minutes (range = 67-340 minutes, median = 172 minutes). Because the PACU stay was relatively short, we do not think that a shift of critical care from the ICU to the PACU occurred in our experience. Because many LT recipients have a relatively brief ICU stay, we think that this change in care can be made successfully by other LT programs as well. This approach can also be beneficial for other surgical practices using a common ICU through a halo effect: overall critical care services, ICU bed utilization, and staffing can be optimized, especially in institutions with large LT programs.

Although our study shows a low failure rate for fast-tracking (ie, a low rate of admissions to the ICU after a postoperative ward transfer from the PACU), we cannot determine the number of patients who were transferred to the ICU but could have been fast-tracked. Our data do not allow a retrospective evaluation of whether logistics determined ICU admissions after LT (eg, the availability of a 1:1 nurse-to-patient ratio in the surgical ward). We identified 40 patients who stayed in the ICU for 1 day or less. The recipient and donor characteristics of these patients were similar to the characteristics of those who were fast-tracked. However, in comparison with the fast-tracked recipients, these patients required more intraoperative transfusions, and their operative times were significantly longer. A subanalysis showed that there were no differences in the intraoperative transfusion requirements or the operative times between daytime and nighttime operations. However, because the number of these patients was so limited, it is not possible for any firm conclusions to be reached at this time.

This study and the data reported herein represent the largest published experience with fast-tracked LT recipients after the implementation of the MELD system. This study also presents results for consecutive LT recipients without a preselection bias from a single large-volume LT center with relatively stable preoperative selection criteria and postoperative care. During the study period, no substantial changes in the clinical care of patients were made. There was consistency in the anesthesiology, surgery, and critical care staff. This study documents the elements of the patient care approach at Mayo Clinic Florida that correlate with the safe implementation of fast-tracking and the complete elimination of an ICU stay. These elements are common and might be replicated in other transplant programs, and they offer the possibility of improved patient outcomes with attendant cost savings. Significant limitations include the restriction of this practice and the observations to a single large-volume LT center and the inability to prospectively study patients who were otherwise similar and were randomized to fast-tracking versus ICU admission. The findings in this cohort should be validated by different institutions, perhaps with prospective protocols. Although a direct cost analysis was not undertaken, the practice of bypassing the ICU without increases in morbidity and mortality would be expected to achieve significant cost savings. There are other potential factors that could play a role in the perioperative management and outcomes of LT recipients. The preoperative cardiopulmonary function of recipients, a history of significant encephalopathy, and previous upper abdominal surgical operations undoubtedly could be factors complicating LT and subsequent management, and they should be included in future detailed analyses.

In conclusion, we have reported the largest single-center experience with fast-tracking to the surgical ward after LT. Our analysis has delineated factors that play significant roles in successful fast-tracking. Early-extubation and fast-tracking protocols should ensure patient safety and be tailored to fit an institution's resources. Contributions from all surgeons, anesthesiologists, and critical care specialists are essential. Further studies should be conducted to identify pretransplant comorbid conditions and intraoperative factors in order to obtain a more granular picture that will result in cost-savings without patient safety being compromised.

Acknowledgements

Authors thank Kendra Hentkowski, Anne T. Few and Jefree A. Shalev for their valuable assistance with this manuscript.

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